SP485R 1/10th Unit Load RS-485 Transceiver FEATURES Allows Over 400 Transceivers On A Transmission Line ( / 0th Unit Load) High Impedance on Receiver Inputs (R = 150k typical) IN Half-Duplex Configuration Consistent With Industry Standard Pinout -7V to + 2V Common Mode Input Voltage Range Low Power Consumption (250mW) Separate Driver and Receiver Enable DESCRIPTION The SP485R is a pin-to-pin equivalent to our existing SP485 product and offers a high receiver input impedance. The higher receiver input impedance allows for connecting over 400 transceivers on a single transmission line without degrading the RS-485 driver signal. The device is packaged in a 8-pin plastic DIP or 8-pin narrow SOIC. Figure 1. Typical Application Circuit Exar Corporation 48720 Kato Road, Fremont CA, 94538 50-668-70 7 www .exar.com SP485R 00 072309 ABSOLUTE MAXIMUM RATINGS These are stress ratings only and functional operation Power Dissipation of the device at these ratings or any other above those 8-pin NSOIC................................................. 000mW indicated in the operation sections of the specifications ( = 62C/W) JA below is not implied. Exposure to absolute maximum 8-pin PDIP.................................................... 000mW rating conditions for extended periods of time may ( = 62C/W) JA affect reliability. V .......................................................................+7V CC Storage Temperature.......................-65C to +150C ELECTRICAL CHARACTERISTICS Typically 25C V = +5V unless otherwise noted. CC PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS LOGIC INPUTS V 0.8 Volts IL V 2.0 Volts IH LOGIC OUTPUTS V 0.4 Volts I = -3.2mA OL OUT V 2.4 Volts I = .0mA OH OUT RS-485 DRIVER DC Characteristics Open Circuit Voltage 6.0 Volts Differential Output Voltage .5 5.0 Volts R = 54, C = 50pF L L Balance +/-0.2 Volts V - V T T Common-Mode Output 3.0 Volts Output Current 28.0 mA R = 54 L Short Circuit Current +/-250 mA Terminated in -7V to + 2V RS-485 DRIVER AC Characteristics Maximum Data Rate 5 Mbps R = 54, L Output Transition Time 30 ns Rise/fall time, 0% to 90% Propagation Delay, t 60 00 ns See Figures 4 & 6, R = 54, PLH DIFF C = C = 00pF L L2 Propagation Delay, t 60 00 ns See Figures 4 & 6, R = 54, PHL DIFF C = C = 00pF L L2 Driver Output Skew 5 5 ns see Figures 4 and 6, t = t - t SKEW DPHL DPLH RS-485 RECEIVER DC Characteristics Output Voltage Low, V 0.4 Volts OL Output Voltage High, V 2.4 Volts OH Tri-State Output Current +/- A 0.4V V 2.4V RE = Vcc OUT Exar Corporation 48720 Kato Road, Fremont CA, 94538 5 0-668-707 www .exar.com SP485R 00 072309 2